The purpose of the proposed research is to elucidate the natural history of coronary heart disease (CHD) by its investigation in a large biethnic community in south Texas, Nueces County/Corpus Christi. The population of approximately 300,000 is 49% Mexican American and 45% Anglo (non-Hispanic White) and affords potential comparisons between ethnic groups expected to differ in their rates and patterns of occurrence of CHD. Incidence of hospitalization for acute myocardial infarction (MI), time to recurrence of MI, and duration of survival post-MI will be carefully determined for both groups, for analysis in relation to prognostic factors ascertained at initial hospitalization and periodically post-discharge. We anticipate that a total of 3200 definite or possible MIs, according to standardized diagnostic criteria, will be identified between 10/87 and 12/91; and an average of 27 months of followup will accrue for those discharged alive. The number of endpoint events in the cohort during follow-up is projected to be as many as 250 in-hospital deaths and 450 late deaths and 225 reinfarctions among those in active followup by periodic telephone interviews. The resulting information will be most significant for its insights into the natural history of CHD in two distinct ethnic groups; the first description of such information for the Mexican-American population; and its potential for helping to explain population differences in CHD mortality and to point to preventive or therapeutic interventions (or both) as likely to influence this process.